Raging Blow -- We want this to be an ability that can't be used 100% of the time. We don't want Fury to have very static (and boring) rotations. We're going to try to keep Fury enraged a lot without it being 100% up time (somehwere in the 75% range sounds better). As such, we're not crazy about a design that lets you hit Raging Blow whenever you want. It just waters down the ability. (In fact, we feel the same way about Execute and are considering redesigning Sudden Death for Arms). We think we can make Fury's use of enrage predictable enough without being totally under player control that your dps won't fluctuate wildly from fight to fight.
Fury in the Blood -- I think a little bit of the "we won't be able to use our utility abilities correctly" is a little overblown. For starters, you don't need to use Bloodrage and Berseker Rage all that much. Fury has a lot of other ways to generate rage, and fears just aren't super common in PvE and you have other ways to break them in PvP. In those situations where they do come up, we think it's an interesting choice. Is the boss going to fear? Maybe you want to save your Berserker Rage for a few seconds and use it then. There are going to be very, very few fights where it's a true dps loss to delay or save your Berserker Rage for the right time. Frankly, we'd rather have encounters feel more different like this, where abilities are more valuable or have to be used differently sometimes. I compare it to Arcane's mana gem talent. Sometimes you want to use the gems for mana and sometimes spellpower and sometimes both. That makes the decision on when to use the gem deeper than just "on cooldown."
Now all of that is really just an endorsement of Raging Blow, not Fury in the Blood. In fact, with Raging Blow being the primary reason to stay enraged, we're just not sure we also need the bonus damage from the Fury in the Blood abilities. With say Enrage and Death Wish providing the enrage sometimes, you should have to fall back on Bloodrage and Berserker Rage less often, which should let you save them for emergencies more often (but not always, as I said above).
In short, we like Raging Blow, but not Fury in the Blood and will likely redesign the latter.
